1. Field of the Invention
The present disclosure relates generally to toner cartridges used in electrophotographic imaging devices such as a printer or multifunction device having printing capability, and in particular to toner delivery systems used for toner cartridges.
2. Background Information
In a typical electrophotographic imaging device such as a printer, a toner cartridge supplies toner to the apparatus through a toner supply port in the toner cartridge. In such toner cartridges, a torque based toner level sensing method is commonly used to provide an indication for the customer when the toner cartridge is low and out of toner. A one-sided paddle is incorporated within the toner cartridge to determine the torque at a known position to sense the level of toner in the sump. The paddle is driven by a motor and gear train to rotate about the interior of the toner cartridge. A film strip, typically made of polyethylene terephthalate (PET) material, such as MYLAR®, may be connected to the distal ends of the paddle to sweep toner from along the wall of the interior into the toner supply port. However, in such toner cartridges, having any portion of the paddle touching the housing wall would interfere with the torque based toner level measurement. As such, toner delivery may not be fully efficient such that not all of the toner is successfully delivered at the end of the toner cartridges life and there may still be residual toner left in the toner cartridge. To get this residual toner out of the cartridge customers remove the toner cartridge from the printer and shake. However, shaking the toner cartridge may sometimes result in dropping the cartridge, toner leaks and toner cartridge malfunction.
A need therefore exists for a toner delivery system that eliminates the need for shaking of the cartridge, a toner delivery system that provides a reliable and consistent supply of toner to an image forming apparatus until the toner cartridge is empty and minimizes the residual toner left in the toner cartridge at the end of life.